The present invention concerns a circuit arrangement for electrically coupling a direct-current source to a direct-current load and a method of interrupting a direct-current connection between an output of a direct-current source and an input of a direct-current load. The invention further concerns the use of an isolating switch for interrupting a direct-current connection.
Solar generators generate a direct current which is transmitted to a connected load. In that case the solar generators generate current as soon as a load is connected and can receive current and there is sufficient incident solar radiation. It is therefore necessary to provide a circuit-breaker device which in a fault situation can separate the solar generator from the load.
Various solutions are known from the state of the art, which are based on DC switches or circuit arrangements for power reduction by way of pulsed semiconductors. EP 1 657 797 discloses for example a circuit arrangement with solar generators and connected inverter which in a fault situation, when the inverter is to be separated from the solar generator, progressively interrupts the circuit from the solar generator to the inverter and back by means of a clock module and thereby puts the solar generator into an idle no-load condition. As soon as that no-load condition has occurred current no longer flows between the solar generator and the inverter and the connection can be separated.
A disadvantage in that respect is the comparatively great and complicated involvement in preparing for such a circuit-breaking situation. In addition the entire current must also flow by way of the clock module in normal operation, that is to say the predominant part of the time. That gives rise in particular to heat losses in the clock module.